A pyrene-appended naphthalimide-dipicolylamine was developed as a ratiometric fluorescent probe for Zn²⁺ ions. This probe displayed a ratiometric change in the fluorescent intensities at 385 and 530 nm corresponding to the emissions of pyrene and naphthalimide units for Zn²⁺ over other metal ions, allowing for a precise quantitative analysis of the Zn²⁺ ion. The fluorescent color change was also visualized from blue to green. We demonstrated that probe recognized Zn²⁺ ions based on a 1:1 stoichiometric binding event and it showed a high sensitivity (limit of detection: 10.5 nM) and a rapid detection time for the Zn²⁺ ion. In addition, the ratiometric change was found to be highly selective for the Zn²⁺ ions even in the existence of other competitive metal ions including Cd²⁺, Pb²⁺, Hg²⁺, Ni²⁺, Co²⁺ and Cu²⁺ ions. Moreover, this probe was able to detect Zn²⁺ ion in a wide pH range of 4-11 and it could be efficiently recycled by treating ethylenediaminetetraacetic acid (EDTA). Furthermore, this probe was successfully utilized for measurement of Zn²⁺ concentration contained in drug commercially available zinc supplement.